A need exists for an improved surgical instrument to enable safe and efficacious removal of living tissue during diagnostic and therapeutic medical interventions. While instruments have been designed with simple blades and rotors for cutting or chopping tissue, they do not provide precision removal of a tissue specimen of a predetermined length, width and depth. It is also difficult for such instruments to harvest tissue from a patient under realistic clinical conditions and to safely access remote locations in the patient. Further, such instruments lack the capability to effect separation of tissue planes at a site prior to tissue removal, or to deliver therapeutic agents to tissue. For example, devices for removal of arterial blockage, often called artherectomy catheters, have distal ends with cutting blades of various types, such as longitudinal, helical, or circular cup-shaped blades. Often such blades are presented through opening(s) at the distal end of the devices. Examples of artherectomy catheters may be found in U.S. Pat. No. 4,979,951, 5,074,841, or 5,643,296. Other surgical cutting device, such as useful in endoscopic bone surgery, have helical shaped rotatory cutters extending in through a tube having multiple openings to receive tissue, such as described in U.S. Pat. No. 4,867,157. Although such devices may be useful for their particular limited applications, they do not generally control for precise tissue sample size or cutting depth, mechanical tissue engagement, preservation of biopsy specimen for subsequent examination, or injectable fluid delivery.
One application for removal of tissue relates to the esophagus, and in particular Barrett's esophagus, a disease associated with GERD or gastroesophageal reflux disease representing a precancerous condition of the mucosal lining the esophagus. It is important that in diagnosing Barrett's esophagus, cancer, or other abnormality in the esophageal lining, that a biopsy be taken for examination. Currently, a flexible endoscope or gastroscope is used to locate the suspected tissue in the esophagus. Through a narrow (1 to 3 mm) channel in the endoscope, long, thin biopsy forceps (typically two sharp edged hemispheres that close onto each other) are passed and used to engage and collect few small bites of the tissue at different esophageal locations. Accurate forceps placement remains problematic as does frequent bleeding at the biopsy site, further obscuring accurate tissue harvest. As such imprecise biopsy forceps sampling may miss diseased tissue, it would be desirable to obtain a larger, well controlled specimen of tissue from the esophagus, thereby reducing the risk of misdiagnosis.
The physical location of such tissue in the esophagus makes alternative non-invasive medical intervention along the gastrointestinal tract difficult. One approach is to inject saline submucosally using a flexible endoscope, and then a snare to capture an area of tissue. However, this approach may be limited to capturing nodular areas, rather than a long segment of the esophageal lining. A further approach described in U.S. Published Patent Application No. 2001/0049509, filed Dec. 6, 2001, provides an endoscopic treatment system for treating and removal of mucosal lining from the esophagus by tools extending through endoscopic channels, such as a syringe needle for localized injections of the mucous membrane, forceps for gripping mucous membrane, and knives(s) for peeling or cutting off the mucous membrane.
Like other surgical cutting instruments described earlier, it is difficult using these approaches to remove tissue to precisely control the cutting depth into the esophageal lining, which can result in inadequate removal of mucous membrane or inadvertent removal of sub-mucosal layers leading to possible esophageal wall perforation. Further in the case of U.S. Published Patent Application No. 2001/0049509, the use of forceps and knifes represents a manual time consuming process prone to human error. A further problem of these approaches is that if the wound in the esophageal lining is to be closed, such as by suturing (i.e., stitches) or other closure devices, there may not be proper tissue edges on either side of the wound to appose, resulting in failure of stitches or tearing of stitches through the tissue, and may lead to failure of primary healing. Thus, it would further be desirable to remove tissue from the lining of the esophagus with a single instrument enabling remote location in the esophagus with precise control of the cutting shape and depth, and moreover can provide tissue edges on either side of the resulting wound that can be well apposed for primary closure of the wound site. Such proper apposition of tissue edges is necessary when a wound is closed to induce primary healing, and thereby rapidly provide a strong more durable wound closure than where accurate wound edge apposition is not present. Such wound closure in tubular structures having mucosal lining is especially difficult due to the slippery nature of such tissue, thus, it would still further be desirable to stabilize the tissue prior to being cut.